|“||... The hero's soul, cursed blade shall reap...||”|
–The Great Prophecy referring to Annabeth's knife
Annabeth's Knife is Annabeth Chase's primary weapon, which she is very skilled in using it. She uses it very frequently, as it was a gift from Luke Castellan when she was seven. This knife is made out of celestial bronze which makes it a weapon for monster killing."
Originally, the knife or "dagger" belonged to a young girl who was saved from dying in an accident by Halcyon Green. She gave him the dagger as a thanks for saving her life.
Hal kept the dagger during his punishment,given to him by Apollo, in his childhood home until the arrival of Luke Castellan and Thalia Grace. He gave the dagger to Luke after they came up with a way to escape the mansion and Hal sacrificed himself to save them.
After meeting Annabeth Chase, Luke replaced the hammer she was using with the dagger/knife he had received from Hal. Annabeth was only seven years at the time, while Luke was fourteen and Thalia was twelve. Luke made a promise to Annabeth that he would be there for her when he gave her the knife so that she could defend herself from monsters that were chasing them. It is her weapon of choice because when Luke gave it to her, he told her that only the fastest and cleverest of warriors could wield the weapon.
Annabeth is very skilled with the knife, although she has been trained to wield a sword as well. When Luke betrayed her and joined Kronos at the end of The Lightning Thief, it became cursed because of his broken promise. It is also the knife that Luke used to kill himself in The Last Olympian, by stabbing himself in his Achilles Heel (which was under his left arm), in order to destroy Kronos' spirit in his body so that Olympus could survive and that the Western Civilization could live on.
Annabeth leaves the knife on the Argo II, while she goes to New Rome. When they leave New Rome and set off to Charleston Harbor, Annabeth goes to the Battery with Piper and Hazel where they meet Aphrodite. When Octavian and the Romans attack, she tosses it into the water, to send out a signal to Percy so he could help them. Octavian then complains, "That could've been evidence. Or spoils of war!". She also uses it to shatter the sacred cavern of Mithras and later it is dropped into Tartarus along with Daedalus' Laptop.